There has heretofore been known a coordinate measuring instrument wherein a signal producing probe such as a touch signal probe to produce a signal directly or an approach signal probe to produce a predetermined approach signal indirectly is tridimensionally moved to measure a configuration of a work to be measured. In general, the coordinate measuring instrument of the type described is of such an arrangement that supports are provided on a bedplate in a manner to be movable in the longitudinal direction, i.e. a direction of Y-axis, a slider laterally racked across the top ends of these supports in a manner to be movable in the lateral direction, i.e. a direction of X-axis, and a Z spindle is provided in a manner to be movable in the vertical direction, i.e. a direction of Z-axis. Herein, a stacking construction is adopted that the supports are assembled onto the bedplate, the slider onto the supports and the Z spindle onto the slider, successively.
In consequence, unless rigid structures are successively adopted from the bedplate to the Z spindle, it is difficult to secure the accuracy. This causes such disadvantages in a so-called automatic coordinate measuring instrument, wherein the respective axes are of automatically driven type, that a driving source is raised to a high horsepower one due to a high weight load, a control system is made to be a high class one due to a high inertia, or feed at high speed becomes difficult to do. Furthermore, the general construction is large-sized, which leads to an economical disadvantage.
Furthermore, in the coordinate measuring instrument, replacement of the touch signal probes is performed mainly, the means for mounting and removing is screwing or the like, which is not automatic and requires labor hours. Further, such touch signal probes, which should be replaced one with another in accordance with the use applications, must be prepared each time, and an angle of a measuring element of the touch signal probe, which has been mounted, should be varied in accordance with the configuration of the work. In any case, the operation relating to the touch signal probe disadvantageously requires labor hours.
The present invention has as its object the provision of a coordinate measuring instrument capable of improving the operating efficiency in carrying out an operation of mounting or removing a touch signal probe, an operation of changing a direction of a measuring element and the like in the coordinate measuring instrument.